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Re: good results with new coil
From: Bert Hickman[SMTP:bert.hickman-at-aquila-dot-com]
Reply To: bert.hickman-at-aquila-dot-com
Sent: Tuesday, August 05, 1997 9:05 AM
To: Tesla List
Subject: Re: good results with new coil
Tesla List wrote:
>
> From: Jason Judd[SMTP:jason.judd-at-anu.edu.au]
> Sent: Tuesday, August 05, 1997 12:32 AM
> To: Tesla List
> Subject: Re: good results with new coil
>
> > From: Peter Electric[SMTP:elekessy-at-macquarie.matra-dot-com.au]
> > Reply To: elekessy-at-macquarie.matra-dot-com.au
> > Sent: Saturday, August 02, 1997 4:30 AM
> > To: Tesla List
> > Subject: Re: good results with new coil
> >
> > Tesla List wrote:
> > >
> > > From: Jason Judd[SMTP:jason.judd-at-anu.edu.au]
> > > Sent: Thursday, July 31, 1997 7:27 PM
> > > To: Tesla List
> > > Subject: good results with new coil
> > >
> <SNIP>
>
> > 18" is pretty good from a 10Kv 30Ma. Sounds like your coil is a good
> > performer.
> > Be a bit carefull putting 15Kv across your 1mm Cap. Richard Quick and
> > co. recommend around 2mm for this voltage.
> >
> > Also try a bit of compressed air on your gap, even if its just a
> muffin
> > fan or even better, an old vacuum cleaner motor. They have stacks of
> > them at the revolve and it did wonders for my coil.
> >
> > Cheers,
> >
> > Peter E.
> >
> >
> >
>
> Sounds like I am in for trouble with my cap. I have successfully run
> it at 15KV now, but I am only game to run it for about 5 seconds at a
> time. There is only 15MM between the flashing and edge of the poly.
> When I was building it I thought that oil would sort out the problem as
> I have made another dry fired cap with only about 20MM to the edges and
> have had no problems even at 15Kv. It was made from 4MM perspex though
> ( and not rolled) :)
>
> What is the difference in losses between polyethylene and perspex does
> anyone know ? If my cap does blow I think that I will just go back to
> flat stacked perspex plates.
>
> Also I did try a muffin fan and found at low powers levels it made the
> sparks longer and fatter, but when I started to raise the power level
> the fan seemed less effective.
>
> Cheers
>
> Jason
Jason,
Polyethylene is a much better (lower loss) dielectric than perspex (same
as plexiglas or PMMA). PMMA is about 200 - 500 times lossier - this will
translate into hot capacitor dielectrrics, not hot sparks. It'll work,
BTW, just like glass plate or bottle caps will work, but you won't get
nearly the performance as with a LDPE cap.
Safe cappin' to you!
-- Bert --